Edge concerns

Edge concern interviews cover CDN cache-control, redirects and edge functions, and WAF protection—using the edge without breaking correctness or hiding data ownership.

Subtopics: CDN and cache-control, edge redirects and functions, and WAF and edge protection.

On interviews: design cache headers for public vs personalized content, explain when edge functions are worth operational cost, and how you monitor WAF false positives.

Common pitfalls: CDN caching Set-Cookie responses, edge rewrites that bypass app authorization, and WAF as the only security layer.

Checklist:

• Classify responses as public, private, or surrogate-cacheable.
• Keep edge logic stateless and observable.
• Purge and shield origins during traffic spikes.
• Treat WAF as defense in depth with app validation.